Almost all Cisco networking devices (routers, switches, firewalls, etc.) include an NTP implementation. Some routing protocols require synchronized time, and of course accurate time is needed for security logging purposes.
The Cisco implementation is based on The Reference NTP Implementation
, but has been modified to:
- run on the networking device hardware, which can be architecturally quite different from a general purpose server or workstation
- be configurable using Cisco management tools and configuration files
Routers and switches are not intended to be general purpose NTP servers.
There is no reference clock support built into Cisco's implementation; external servers must be configured.
Related topics: Cisco NTP pages